The invention relates to the field of thrust reverser systems for aircraft turbomachines.
It relates more specifically to the systems comprising thrust reversal gratings with which the double-flow turbomachines are equipped.
The invention relates also to an aircraft comprising turbomachines equipped with such thrust reverser systems. It applies preferentially to commercial aeroplanes.
Thrust reverser systems are for example known from the documents FR 2 935 444 and FR 2 935 354. Among the different thrust reversal principles implemented on aircraft turbomachines, reversal grating systems are known, that are provided with passages oriented in such a way as to redirect forwards the air originating from the secondary channel, in order to generate the counter-thrust load. The air is forced to be extracted from this secondary channel through reverser gates at least partially blocking this channel, in active configuration of the system.
On the other hand, in inactive configuration, each reverser gate is in retracted position in which it participates in the formation of the outer wall of the secondary channel, also called OFS (Outer Fixed Structure). More specifically, in this inactive configuration of the reverser system, each gate reconstitutes a part of this outer wall of the secondary channel, within a mobile external nacelle fairing enclosing the reversal gate. In the transition from the inactive configuration to the active configuration, the mobile external fairing is displaced backwards by cylinders so as to release the grating, and to bring the reverser gates into their position of blocking of the secondary channel, via appropriate mechanical kinematics.
This principle, although widely used, does nevertheless suffer from a problem of aerodynamic disturbances from the flow of air passing through the secondary channel in inactive configuration of the system. In fact, in this configuration, the flow of air in the secondary channel is disturbed in its passage over the areas of join between the body of the outer mobile fairing, and the reverser gates added to this body. This causes drag and losses of pressure in the secondary channel, which lead to a reduction of the overall performance levels of the turbomachine.
There is therefore a need to optimize the design of these thrust reverser systems, in order to reduce the disturbances of the flow of air in the secondary channel, in inactive configuration of the thrust reverser system.